MENLO PARK — Facebook on Thursday announced new software for Android phones that promises to “put people ahead of apps,” by showing photos and friends’ updates from the social network as the central feature of a smartphone’s homescreen.

The new Home software puts some of Facebook’s most important services front and center on a phone, making them easier to use and in some cases giving less prominence to mobile apps from other companies. Analysts said that may set the stage for more competition in the future with Google (GOOG) and other app-builders.

Home will come preinstalled on a new smartphone made by HTC, but it will also be available starting April 12 as an app for other Android phones through the Google Play store.

Demonstrating the software at Facebook headquarters, CEO Mark Zuckerberg promised a crowd of reporters and analysts that it will “turn your Android phone into a great, simple social device” — making it even easier to check in with friends while standing in line at the store or killing a few minutes between meetings at work.

While phones and computers have traditionally been designed around programs and apps, Zuckerberg said, the new software is intended to emphasize “people first” because it displays photos and updates on the phone’s primary screen automatically — a feature called “cover feed” — without forcing the user to open a Facebook app on the phone.

The software also integrates text messaging and Facebook’s own messaging service in a feature called “Chat Heads,” which displays a small photo of the person sending a message and lets users chat with friends without interrupting other functions or apps on the device.

By making it easier for smartphone users to access Facebook’s services, the company is clearly hoping to increase their “engagement” and deliver more mobile advertising to those users.

Zuckerberg said the new Home software won’t show advertising, to start. But when asked if ads may eventually appear in cover feed, Zuckerberg answered succinctly: “Yup.”

Analysts said the new features are visually attractive and will likely appeal to many Facebook users. But since the software puts so much emphasis on photos and other content from friends on Facebook, it may turn off some people.

But for other people, added mobile tech expert Chris Jones of the Canalys research firm, “there are different levels of willingness to expose themselves to a particular app. Some people like to keep their home screens fairly plain. Some people want to see their own photos, not other peoples’ photos.”

Jones added, “I think a lot of people may be really reluctant to dive into this straightaway.”

The software only works with the Android operating system, made by Google, which means its features aren’t available for iPhones or other gadgets running operating systems from Apple (AAPL) or Microsoft. Facebook has also worked closely with Apple to integrate its services with the iPhone’s operating system, but Zuckerberg praised the open-source Android platform on Thursday because it was designed to be easier for outside developers to build on.

The new HTC phone, called First, will be sold through AT&T for $99 with a two-year contract. Zuckerberg said the app will be available for downloading onto a limited number of Android phones from Samsung and HTC, but the company is working on versions for other Android phones and tablets.

Nearly half of Facebook’s 1 billion active members check the social network regularly on their smartphones or tablets. With more than $300 million in mobile ad sales last quarter. Facebook’s share of the U.S. mobile advertising market grew from zero to nearly 10 percent in 2012, according to eMarketer.

That means Facebook is increasingly competing with Google, which still dominates the market because it shows more mobile ads when people use Google’s search engine and other services on both Android and Apple phones. Facebook users can still turn to those Google services while using the new Home interface, although analysts said Facebook may be able to subtly encourage users to use competing services from Facebook instead.

Contact Brandon Bailey at 408-920-5022; follow him at Twitter.com/brandonbailey